The present disclosure relates to a light emitting device, a light emitting device package, and a lighting system.
A light emitting device (LED) includes a p-n junction diode, whose characteristic includes converting electric energy into light energy and which may be manufactured by combining Group III and Group V elements in the periodic table. The LED may display a variety of colors by adjusting the composition ratio of a compound semiconductor.
The LED emits energy that corresponds to an energy gap between a conduction band and a valance band, which occurs after electrons of an n-layer and holes of a p-layer are combined during application of forward voltage. This energy is typically emitted in a form of heat or light and if emitted in a form of light, it becomes a LED.
For example, since a nitride semiconductor has a high thermal stability and wide band-gap energy, it receives a lot of attention in optical device and high-output electronic device development fields. Especially, a blue LED, a green LED, and an UV LED, which use a nitride semiconductor, are commercialized and extensively used.
However, in relation to the related art, even when a light extraction structure is introduced in order to improve light extraction efficiency of the LED, the light extraction efficiency does not reach a preferred value.